Riblet film for reducing the air resistance of aircraft

Abstract

A riblet film for reducing the air resistance of aircraft, comprising a suspension with magnetic particles enclosed therein. Depending on the pattern of a magnetic field acting on the riblet film, the magnetic field that is acting can be made visible, at least in certain regions, by changing the orientation of the magnetic particles. The riblet film allows an inspection of the aircraft structure located under the riblet film through the riblet film.

The invention claimed is: 
     
       1. A riblet film for reducing air resistance of an aircraft, comprising:
 a suspension comprising a carrier liquid with rotatable magnetic particles enclosed within the carrier liquid, 
 wherein, a magnetic field configured to act on the riblet film will be rendered at least partially visible by an orientation of the magnetic particles. 
 
     
     
       2. A riblet film for reducing air resistance of an aircraft, comprising:
 a suspension comprising a carrier liquid with rotatable magnetic particles enclosed within the carrier liquid, 
 wherein, a magnetic field configured to act on the riblet film will be rendered at least partially visible by an orientation of the magnetic particles, 
 wherein the riblet film comprises a layer with a multiplicity of microcapsules, 
 wherein the suspension is distributed among the microcapsules and respectively enclosed therein. 
 
     
     
       3. The riblet film according to  claim 1 , wherein the magnetic particles comprise colloidal nickel. 
     
     
       4. The riblet film according to  claim 2 , wherein at least one of the suspension or a layer comprising the microcapsules is applied to a substrate serving as a carrier film. 
     
     
       5. The riblet film according to  claim 1 , wherein the riblet film comprises a plurality of ribs which are arranged substantially parallel to one another and have tips. 
     
     
       6. The riblet film according to  claim 1 , wherein the riblet film comprises a plurality of riblets each having a substantially triangular cross section. 
     
     
       7. The riblet film according to  claim 1 , wherein the riblet film further comprises has an adhesive layer arranged to adhesively attach the riblet film onto an aerodynamic surface. 
     
     
       8. An aircraft with a riblet film according to  claim 1  applied to an aerodynamic surface of the aircraft. 
     
     
       9. A method for examining an aircraft structure to which a riblet film according to  claim 1  has been applied, comprising the following method steps:
 generating a magnetic field, 
 making the magnetic field act locally on the aircraft structure to be examined, 
 displaying the generated magnetic field by means of the riblet film, and 
 evaluating the magnetic field displayed. 
 
     
     
       10. The method according to  claim 9 , wherein the evaluation of the magnetic field displayed comprises a comparison with a desired magnetic field. 
     
     
       11. The riblet film according to  claim 1 , wherein the carrier liquid is an oil. 
     
     
       12. The riblet film according to  claim 1 , wherein the carrier liquid is gelatinous. 
     
     
       13. The riblet film according to  claim 2 , wherein the magnetic particles comprise colloidal nickel. 
     
     
       14. The riblet film according to  claim 2 , wherein the riblet film comprises a plurality of ribs which are arranged substantially parallel to one another and have tips. 
     
     
       15. The riblet film according to  claim 2 , wherein the riblet film comprises a plurality of riblets each having a substantially triangular cross section. 
     
     
       16. The riblet film according to  claim 2 , wherein the riblet film further comprises has an adhesive layer arranged to adhesively attach the riblet film onto an aerodynamic surface. 
     
     
       17. An aircraft with a riblet film according to  claim 2  applied to an aerodynamic surface of the aircraft. 
     
     
       18. A method for examining an aircraft structure to which a riblet film according to  claim 2  has been applied, comprising the following method steps:
 generating a magnetic field, 
 making the magnetic field act locally on the aircraft structure to be examined, 
 displaying the generated magnetic field by means of the riblet film, and 
 evaluating the magnetic field displayed. 
 
     
     
       19. The method according to  claim 18 , wherein the evaluation of the magnetic field displayed comprises a comparison with a desired magnetic field. 
     
     
       20. The riblet film according to  claim 2 , wherein the carrier liquid is one of an oil or gelatinous.